The Passwords

A man worked for a high-security institution, and one day he went in to work only to find that he could not log in to his computer terminal. His password wouldn't work. Then he remembered that the passwords are reset every month for security purposes. So he went to his boss and they had this conversation:
Man-"Hey boss, my password is out of date."
Boss-"Yes, that's right. The password is different, but if you listen carefully you should be able to figure out the new one: It has the same amount of letters as your old password, but only four of the letters are the same."
Man: "Thanks boss."
With that, he went and correctly logged into his station.
What was the new password?
BONUS: What was his old password?